JPH0367826B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a taper grinding device that grinds a tapered portion of a workpiece having a tapered portion with high precision.

[Prior Art] The taper grinding work in a conventional grinding device of this type will be explained in detail based on FIGS. It is rotatably supported by a center 3 held by the main shaft 2 of the headstock 1, and by another center 4 at the right end. A reference end face Wa is formed on the workpiece W, and a reference end face Wa is formed at a position that is a distance A forward from the end face Wa (this distance is a distance that needs to be precisely machined for the workpiece W) and has a length a. A tapered portion Wb is formed (with respect to the axial direction of the workpiece, the direction from the reference end surface to the tapered portion direction is referred to as the front in this specification,
The opposite is called backward).

The taper portion Wb is ground using the grindstone G in the state shown by the two-dot chain line in FIG. W is retreated to the position shown by the two-dot chain line in FIG. 1 by moving a traverse table (not shown) rearward (provided on the back side in the direction perpendicular to the plane of the paper). This retreat amount is
The reference end face Wa is the filler F of the end face sizing device (the sizing device is installed on the base, which is a fixed member, and the filler is movable in the direction of the workpiece or in the opposite direction). This is a predetermined constant amount up to just past the tip position f. Further, as the traverse table moves backward, the pivot p fixed to the table also moves by the same amount, and becomes the position indicated by the two-dot chain line p in FIG.

Next, as shown in FIG. 2, the filler F is advanced in the direction of the arrow, and then the main shaft 2 of the headstock 1 is advanced in the direction of the arrow. In other words, the main spindle 2, centers 3, 4, and workpiece W are moved forward together to reach the reference end surface.
Move until Wa contacts filler F. In this case, the pivot p is fixed to the traverse table and therefore does not move.

After a signal is issued from the end face sizing device upon contact with the filler F, the traverse table moves backward by B as shown in FIG. 3, and the workpiece W is placed at the solid line position. In this case, the pivot p also moves back by the same amount B.

Next, the swivel table (not shown) placed on the traverse table rotates around the pivot p, so that the workpiece W (and the headstock 1,
The main shaft 2, centers 3 and 4 (integrated body) assumes a rotating position as shown by the two-dot chain line, and the grindstone G moves forward as shown by the two-dot chain line to grind the tapered portion Wb.

In this way, in the conventional device, the end face positioning is performed by advancing the main shaft 2, so that the position of the pivot p remains unchanged regardless of variations in the end face position.
Therefore, the swivel table is rotated by a predetermined angle around the pivot p at the fixed position,
After that, by sending a grindstone and grinding, the length A from the reference end face Wa to the start point of the tapered part can be kept constant for all workpieces.

[Problems to be Solved by the Invention] However, in order to move only the main shaft relative to the pivot in this way, a special headstock must be used, which is expensive.

In addition, as an earlier application by the present applicant, there is Japanese Patent Application No. 59-055486, in which an end face sizing device is fixed on a bed, and the workpiece to be machined relative to the model workpiece is Since the configuration indirectly measures the error amount of the reference end face, it takes time to position the end face by positioning the traverse table.
The disadvantage is that the operation is cumbersome and therefore grinding takes time.

[Object of the Invention] The present invention aims to solve the above-mentioned conventional drawbacks by providing an absolute end face position measuring device on a traverse table and measuring the amount of error between the reference end face of the workpiece to be machined and the reference end face of the model workpiece. directly measured,
To provide a taper grinding device that simplifies the configuration of the headstock by omitting the axial movement function of the spindle by making corrections when the traverse table moves and when the grindstone moves forward, and at the same time achieves cost reduction. It is something.

[Means for Solving the Problems] The present invention can be illustrated as a conceptual diagram as shown in FIG. This is a general term for a drive source (for example, a servo motor or a stepping motor) for reciprocating the 210, a rail for facilitating the reciprocation, and a drive circuit for driving the drive source. Swivel table drive device 206
includes a drive source (for example, a servo motor, a stepping motor) for rotating the swivel table 209 in response to a signal from the numerical control device 200, a power transmission mechanism such as a gear for making the rotation easy and reliable, and the drive. A general term for drive circuits that drive sources. Further, the grindstone feeding device 205 includes a drive source (for example, a motor similar to the above) for sending the grindstone 208 in the direction of the workpiece in response to a signal from the numerical control device 200, and a drive source (for example, a motor similar to the one described above) to move the grindstone 208 in that direction easily and reliably. This is a general term for the rail for grinding, the grindstone head, and the drive circuit that drives the drive source.

The error detection unit 202 in the numerical control device 200 is a part that receives a signal emitted from the sensor 211 and detects an error between the reference end face of the workpiece and the reference end face of the model workpiece. Here, the sensor is preferably an absolute end face position measuring device (a commercially available end face sizing device may be used), the main body of which is fixed on a driver table or swivel table, and the contactor is oriented in the direction of the workpiece. It is preferable that the contactor is movable forward and backward, and that the contactor swings near the reference end face of the workpiece, and that the amount of swinging is converted into a current value by the action of an actuating transformer and sent as a signal to the numerical control device. The correction unit 203 corrects the amount of movement of the model workpiece to be ground and the amount of feed of the grindstone based on the amount of error detected by the error detection unit 202, thereby adjusting the amount of movement and amount of the workpiece to be ground. This is the part that calculates the feed amount of the grindstone.

Further, the control signal generation section 204 includes the correction section 2
03 generates control signals for driving the traverse table drive device 207, swivel table drive device 206, and grindstone feed device 205, respectively.

[Effects of the Invention] According to the present invention, when grinding a tapered portion, the amount of movement of the workpiece and the amount of feed of the grindstone are corrected according to variations in the reference end face of each workpiece.
It is possible to eliminate the expensive and complicated headstock used in the past, thereby contributing to cost reduction.

In addition, the present invention has a configuration in which the absolute end face position measuring device is fixed to the traverse table and directly measures the error amount of the reference end face of the workpiece to be machined with respect to the model workpiece, so end face positioning by traverse table positioning is unnecessary. Therefore, the machining time can be shortened.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 5 is an overall plan view showing one embodiment of the present invention, and FIG. 6 is a partial side view seen from the direction of FIG. 5. In these figures, FIGS. Components that are the same as those in the figures are given the same numbers and symbols.

The workpiece W has both centers 13 at both ends,
However, the center 13 and the rotating shaft 12 supporting the center 13 only rotate, unlike the conventional devices shown in FIGS. 1 to 3. Unable to move in direction. This is because the headstock 11 is not a special type as in the conventional device, but is an inexpensive immovable type.
The center 14 is supported by a tailstock 15 and is movable in the axial direction so that a workpiece W can be set thereon.

The headstock 11 and tailstock 15 are supported on a bed 16 via a traverse table 17 and a swivel table 19. The traverse table 17 is capable of reciprocating in the front-rear direction (Z direction) by a Z-axis motor 18 fixed to the end of the bed 16. Further, a swivel table 19 on the traverse table 17 is provided so as to be able to turn around a pivot p. This turning movement is caused by the driving of the S-axis motor 20 provided on the side end surface of the traverse table 17, so that the worm 20b at the tip of the output shaft 20a moves toward the table 1.
This is done by meshing with the worm wheel 19a on the end face of No.9.

On the upper surface of the bed 16 in the upper part in FIG. 5, a whetstone head 21 is disposed so as to be able to reciprocate in the direction of the arrow, and a whetstone G is rotatably provided on the whetstone head 21. The reciprocating motion of the grindstone head 21 is as follows:
This is accomplished by an X-axis motor 22 provided on the side end surface of the bed 16 and at the upper part in FIG.

Further, as shown in the lower part of FIG. 5, an absolute side position measuring device T is fixed to the traverse table 17. The measuring device T, as described later,
This is a commercially available device that measures the amount of dimensional variation that inevitably occurs between the reference end surface Wa of the workpiece to be machined and that of the model workpiece. The end of the device T is provided with a contactor 23 that can come into contact with the reference end surface Wa. and contact 23
is capable of moving forward and backward in the vertical direction as shown in FIG. I'm so nostalgic.

In such a configuration, the procedure for grinding the tapered portion of the workpiece will be described below. The position of the reference end surface Wa of the workpiece usually varies due to operational errors. Therefore, first, we will explain the grinding of the tapered portion of a model workpiece manufactured to ideal dimensions with reference to FIGS. 7 and 8.
FIG. 7 shows that after setting the model workpiece W between both centers 13 and 14 as shown by the solid line, by retracting the traverse table 17,
Then, the integral object such as the main shaft 11 is moved by L to the position shown by the two-dot chain line in FIG. 7, that is, the position shown by the solid line in FIG. The distance L in this case is a preset distance for determining the position of the pivot p for turning as shown by the two-dot chain line in FIG. Then, at the position moved by the distance L, the swivel table 19 is rotated around the pivot p, and the grinding wheel G is rotated.
The tapered portion Wb can be ground by moving the grindstone G forward a distance _M10 to the position shown by the two-dot chain line and bringing the grindstone G into contact with the tapered portion Wb.

In contrast to such a model workpiece W, the reference end face Wa of the actual workpiece W varies, and this variation results in a positional deviation of the pivot p, resulting in a taper error.
Therefore, in the present invention, there is provided a program that measures the amount of variation in the reference end face Wa of the actual workpiece W with respect to the model workpiece W using the absolute end face position measuring device T, calculates and corrects the variation in the pivot p position. The memory MEM of the numerical control device 100 shown in FIG.
The arithmetic processing unit CPU executes processing operations while reading the contents of this memory MEM.

Below, Figures 9 to 10 show the means for grinding the tapered part of a workpiece whose reference end surface Wa has varied positions.
Let's explain with a diagram. First, the workpiece W is set between both centers 13 and 14 as shown by the solid line in FIG _. θ is read out (step 101 in FIG. 11). In addition, L is the traverse table 1 assuming the model workpiece W.
7 is the movement amount, _M10 is the movement amount of the grindstone G assuming the model workpiece W, and θ is the turning angle of the swivel table 19. After that, move the absolute end face position measuring device T forward (upward in FIG. 9),
The absolute positional deviation amount e of the reference end surface Wa position of the workpiece W to be machined with respect to the reference end surface Wa position of the model workpiece described above is measured (steps 102 and 103). In other words, the reference end face Wa of the model workpiece is at the position shown by the two-dot chain line in FIG. A certain measuring device T is measured by moving the table 17 to the left. When measuring in this way, Vo...sensor output when the contact comes into contact with the reference end surface of the model workpiece Vx...sensor output when the contact comes into contact with the reference end surface of the workpiece to be machined, e The amount of error can be detected as =K.(Vx-Vo). K is a proportionality constant.

Next, the traverse table 17 is moved backward, and then the swivel table 19 is turned.If the backward movement amount is set to L, the pivot p becomes _p1 in Fig. 9.
When the workpiece W is rotated at this position, the workpiece W will be in the state shown by the two-dot chain line.If the grindstone G is advanced by _M10 in the X direction, the distance A from the reference end surface Wa to the tapered part Wb must be accurately machined. It ends up being a large value even though it shouldn't be. Therefore, as a correction, the amount of retraction of the traverse table 17 is adjusted as shown in FIG.
Lx is calculated using the formula Lx=L−e, and the grinding wheel advancement amount Mx is calculated using the formula Mx=M ₁₀ +esinθ. (Step 105).

Based on the calculation decision, the motor 18 is controlled to move the traverse table 17 by Lx (step 106), and the turning motor 20 is controlled to turn the swivel table 19 by a certain angle θ (step 107). , and a motor 22 for feeding the grindstone.
is controlled and the grinding wheel G moves forward by Mx (step
108), the tapered portion Wb is ground.

After the grinding is completed, the grindstone G retreats, the swivel table 19 pivots and returns to its original state, and the traverse table 17 returns to its original position as shown in FIG. (Steps 109-111).

[Brief explanation of drawings]

1, 2, and 3 are partial plan views showing a conventional grinding device, FIG. 4 is a block diagram showing the concept of the present invention, and FIG. 5 is an overall plan view showing an embodiment of the present invention. Figure 6 is a front view seen from the direction of Figure 5, Figures 7 and 8 are partially enlarged views of Figure 5 showing the machining status of the model workpiece, and Figures 9 and 10 are normal machining. FIG. 5 is a partially enlarged view showing the processing status of the object, and FIG. 11 is a flowchart showing the operating status of FIG. 5. W...Workpiece, T...Absolute end face position measuring device,
Wa...Reference end surface, Wb...Tapered part, 1, 11
... Headstock, 17 ... Traverse table, 19
... Swivel table, 18, 20, 22 ... Motor, 100 ... Numerical control device.

Claims (1)

[Scope of Claims] 1. A bed, a traverse table that can reciprocate in a uniaxial direction on the bed, and a swivel table that is disposed on the traverse table and can be rotated about a pivot embedded in the traverse table. a grindstone that can move forward and backward with respect to the workpiece held on the swivel table; a traverse table drive device that reciprocates the traverse table; a swivel table drive device that rotates the swivel table; A grindstone feeding device that is driven in one axis direction so as to move forward and backward, a sensor that detects the reference end face of the workpiece, and a signal from the sensor is inputted, and the traverse table drive device, the swivel table drive device, and the A taper grinding device comprising a numerical control device that outputs a control signal to each of the grinding wheel feed devices, the numerical control device inputting the signal from the sensor and detecting the error of the workpiece reference end surface with respect to the model workpiece reference end surface. and an error detection unit that detects the amount of error detected by the error detection unit, and corrects the amount of movement of the model workpiece and the feed amount of the grindstone when grinding the model workpiece, based on the amount of error detected by the error detection unit. a correction unit that calculates the amount of movement of the workpiece and the amount of feed of the grindstone; and a control signal for driving the traverse table drive device, the swivel table drive device, and the grindstone feed device, respectively, based on the results output from the correction unit. A taper grinding device comprising: a control signal generating section that generates a control signal; 2. The main body of the sensor is fixed on a traverse table or a swivel table, the contactor contacts the reference end face of the workpiece, and the error amount of the reference end face of the workpiece is detected by the deflection angle of the contactor. A taper grinding device according to claim 1.